I am in process of lowering a ceiling in a bathroom. I made a note of the wiring to the pull switch but clearly made a mistake when rewiring!
There are two twin and earth cables leading to the pull switch.
The switch has 4 terminals: Earth; A1, A2 and Com.
All were used when I removed it but I cannot figure out the wiring - I keep blowing the fuse.
Any suggestions?

The only time all three terminals are used is when it is used as two way switch. If this were the case normally one of the cables would be three core. However it can be done with two core.

If two way and only if two way supply goes to A1 that with two core between switches will be on it's own.
A2 goes to light and A2 on other switch.
Com connects to Com on other switch.
Other switch with likely be twin switch and there will be a link wire to get line.

A1 and A2 can be swapped and it will still work.

As a single way switch A2 will not be used. And since two cables then reds to com and A1 and blacks connect together with a link block. Since you say it blows fuse I expect it is a single way switch. Have you changed the pull switch as you can get double pole pull switches as well as change over type.

As to colours all line wires should be red or brown and where they are not they should have sleeves or tape to show they are line. This often falls off and you are left with unmarked cables. Neutrals will be black or blue. In real terms electricians often don't bother marking and there is no convention as to using wrong colours of course so likely colours will not help you.

Brilliant, thanks guys (thats male and female!) It works a treat now! (I hadn't recorded accurately the terminals and forgot about the additional terminal block for the neutral - I'd logged it as a terminal on the switch!)

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